The functionality afforded mobile radio communications devices such as cell phone handsets has been increasingly defined by reference to the Third Generation Partnership Project (3GPP) proposals and standards and which has focused most recently upon ongoing improvements to the Universal Mobile Telecommunications System (UMTS) such as the Long Terminal Evolution (LTE) ongoing improvement thereto. The present invention relates in particular to 3GPP LTE compatible wireless communication systems and in particular E-UTRAN resources which can employ relatively small building-focused cells such as so-called femtocells.
The User Equipment (UE) forming the mobile terminal devices found for example within UMTS systems can benefit from increasingly diverse functionality. One such feature, which can prove particularly advantageous within a femtocell environment, is CSG functionality.
Within a CSG arrangement, a group of one or more cells, e-NodeBs or base stations or otherwise, are provided for which access is restricted to a limited group of one or more users. The members of that restricted group can benefit from their access to the sub group of cells due to the specific/improved services available via those restricted cells.
A CSG is commonly administered by a network operator wishing to reserve access to certain cells within their mobile network. In this manner, an identifier, such as a CSG ID is commonly broadcast by each restricted cell, by way of its system information. Each UE operating within the network may only select such a restricted cell if the broadcast CSG ID is already found within a list stored within the UE. Any appropriate configuration of such list or lists, can be provided and they can commonly comprise a so-called “operator controlled CSG list” and/or and an “allowed CSG list”. Such lists are commonly stored within the USIM of the UE.
A hybrid CSG cell can also be provided that comprises a CSG cell for access by permitted users, by way of operator subscription, but also by some users that do not have an operator subscription.
Automatic selection can then be made responsive to a match between the CSG ID broadcast by a restricted cell, and the content of the “operator controlled” and “allowed” lists stored in the UE. Alternatively, or in addition, the user can manually search for CSG cells of potential interest and, once found, request the UE to attempt to register to a restricted cell even though the CSG ID is neither within its “operator controlled” or “allowed” CSG lists. In spite of such absence from the lists, should registration to the restricted cell prove successful, the CSG ID of that selected cell can then be added to the “allowed CSG list”.
Thus, automatic and manual registration to the restricted cell is possible.
Insofar as the selection of CSG IDs stored within the UE and, in particular within the “operator controlled CSG list” can be determined by the network operator, further control functionality is afforded the operator insofar as the operator can selectively inhibit the use of the above-mentioned “allowed CSG list”. Accordingly, although a manual selection process might have led to successful registration to a restricted cell, the aforementioned inhibition can be employed by the operator such that the CSG ID of that cell is not subsequently added to the “allowed CSG list” so as to inhibit subsequent automatic selection of that cell.
Insofar as the user-controlled CSG list within the UE, i.e. the above-mentioned “allowed CSG list”, can therefore be inhibited by the network, disadvantageously limiting and potentially problematic scenarios can develop should the UE, by performing a manual CSG selection, attempt to move to a CSG cell whose identity is not found within the “operator controlled CSG list”. That is, in further detail, if, for some reason, the radio signal quality derived from the restricted cell remains insufficient, a different cell which may not be restricted is likely to be selected by the UE. However, as and when the radio signal from the restricted cell improves, automatic reselection of that restricted cell will not be possible and the user will have to again attempt manual selection of the CSG cell. As will be appreciated, the absence of the CSG ID from the “operator controlled CSG list”, and the inhibiting of the “allowed CSG list” serves to prevent such automatic selection.
Yet further, if there are several restricted cells each having the same CSG ID, which might be required to ensure proper coverage within a certain area, for example several rooms within a building accordingly femtocell arrangement, the other restricted cells will not be selected automatically. As the UE moves cells, even though the signal from the selected cell might again become too weak another related restricted cell providing the appropriate service will not be automatically selected due, as noted above, to the absence of these CSG identified from the “operator controlled CSG list” and the inhibiting of the “allowed CSG list”.
In situations in which the restricted cells are likely to provide specific and/or such improved services, such scenarios are quite clearly disadvantageously limited and repeated manual intervention is required each time in an attempt to resume such services.
Various control and management arrangements for CSG scenarios are known in the current art and one example comprises the subject matter of US-A-2010/0110945. This document discloses a system and method for providing CSGs within a packet-based wireless communications system and relates, in particular, to a manner in which CSG identities are handled within the UE for the performance of cell selections and re-selections.
Illustrative of the nature of the problems and limitations found in the prior art, it is noted that the subject matter of US 2010/0110945 has no disclosure nor suggestion as to how to handle CSGs that are not allowed in the whitelist due in particular to network operator inhibition.
Further, the signaling arrangement disclosed within this document is disadvantageously limited.